1. Field of the Invention
Embodiments of the invention generally relate to data backup systems and, more specifically, to a method and apparatus for file sharing between continuous and scheduled backups.
2. Description of the Related Art
Computer systems and their components are subject to various failures that may result in the loss of data. For example, a storage device used in or by the computer system may experience a failure (e.g., mechanical, electrical, magnetic, etc.) that may make any data stored on the device unreadable. Erroneous software or hardware operation may corrupt the data stored on a storage device and effectively destroy the data stored on an otherwise properly functioning storage device.
To mitigate the risk of losing data, computer networks include backup systems for making backup copies of data stored on various storage devices. One type of backup system includes a dedicated backup server that backs up target data on one or more storage devices used in or by one or more computer systems, such as workstations and/or application servers. The backup server typically backs up the target data periodically according to a schedule. The data may be backed up initially to disk-based storage and then migrated to an archival storage, such as tape-based storage. The backup server may implement any of various known schemes to backup data, including full backups, incremental backups, differential backups, and the like. A full backup is a complete copy of the target data. An incremental backup is a backup that only contains the files that have changed since the most recent backup (either full or incremental). A differential backup is a cumulative backup of all changes made since the last full backup.
Another type of backup system includes a continuous protection backup server that maintains a continuous replica of the target data in real-time. The target data of continuous protection is typically critical data. In a typical continuous backup scheme, block-level changes of the target data are transmitted to the continuous protection backup server as they occur. The replica of the target data maintained by the continuous backup server may itself be backed up to a schedule-based backup server.
In some cases, a combination of continuous and schedule-based backup is performed for given target data. The target data is subject to scheduled-based backup. Critical portions of the target data are also subject to continuous backup. In such a scheme, however, the same data is backed up multiple times resulting in multiple copies of the same data. Such duplication of backup data is inefficient and wastes backup storage space. Accordingly, there exists a need in the art for more efficient continuous and schedule-based backup of target data.